3 FlexShapeGripper 2 Festo AG & Co. KG Picking up, holding and putting down objects – gripping applications have always played a key role in production. At the forefront of industrial automation, Festo is therefore constantly on the lookout for new gripping principles and innovative approaches to solutions for the production systems in the factory of tomorrow. One source of inspiration for new knowledge and future technol- ogies is nature. That is why Festo brought the Bionic Learning Network to life. In an alliance with universities, institutes and development companies, Festo has already studied a range of different grip mechanisms on several occasions using biology as a model. Pick and place of all kinds of shapes In cooperation with the Oslo and Akershus University College of Applied Sciences, Festo now presents a gripper whose working principle is derived from the tongue of a chameleon. The FlexShapeGripper can pick up, gather and set back down several objects with the widest range of shapes in one procedure – without the need for a manual conversion. This is made possible by its water-filled silicone cap, which wraps itself around the items being gripped in a flexible and form-fitting manner. Nature as a model The unique inherent ability to adapt to different shapes gives the FlexShapeGripper its name. In nature, the unique combination of force and form fit demonstrated by the tongue can be observed when the chameleon is on the hunt for insects. Once the chameleon has its prey in its sights, it lets its tongue shoot out like a rubber band. Just before the tip of the tongue reaches the insect, it retracts in the middle, whilst the edges continue to move forwards. This allows the tongue to adapt to the shape and size of the respective prey and firmly enclose it. The prey sticks to the tongue and is pulled in like a fishing line. New impetus from open innovation The aims of the Bionic Learning Network not only include learning from nature, however, but also identifying good ideas at an early stage, and fostering as well as implementing them jointly beyond company borders. The gripper is an outstanding example of the close collaboration by Festo with international universities as part of the network. FlexShapeGripper Soft gripping for various tasks The stimulus for the project was a workshop on the subject of bionics at the Oslo and Akershus University College of Applied Sciences, where Festo presented its current research approaches from the Bionic Learning Network. Two of the students were inspired firstly by the presentation and then by nature itself: as part of their master’s thesis, they presented the bionic grip principle modelled on the tongue of a chameleon. Together with the Festo engineers, the gripper’s material, design and pneumatic components were subsequently optimised and the design concept for the FlexShapeGripper was developed further. Technical configuration of the gripper The gripper consists of a double-acting cylinder, of which one chamber is filled with compressed air whilst the second one is permanently filled with water. This second chamber is fitted with elastic silicone moulding, which equates to the chameleon’s tongue. The volume of the two chambers is designed so that the deformation of the silicone part is compensated. The piston, which closely separates the two chambers from each other, is fastened with a thin rod on the inside of the silicone cap. Form-fitting gripping thanks to inversion During the gripping procedure, a handling system guides the gripper across the object so that it touches the article with its silicone cap. The top pressurised chamber is then vented. The piston moves upwards by means of a spring support and the water-filled silicone part pulls itself inwards. Simultaneously, the handling system guides the gripper further across the object. In doing so, the silicone cap wraps itself around the object to be gripped, which can be of any shape, resulting in a tight form fit. The elastic silicone allows a precise adaptation to a wide range of different geometries. The high static friction of the material generates a strong holding force. Both the holding and the release mechanism are triggered pneumatically. No additional energy is necessary for the holding process. The yielding quality of the compressible compressed air simplifies the coordination between the handling system and gripper during the grip stage. The force and the deformation of the silicone part can be set very precisely with the aid of a proportional valve. This allows several parts to be gripped at once in a single procedure. 01: Universal use: flexible gripping of all types of objects 02: Energy-free holding: even when collecting more than one object in a single procedure 03: Natural role model: the form-fitting slingshot tongue of the chameleon 04: Controlled gathering: picking up and setting down according to the last-in-first- out-principle 01 02 03 04
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